Process for coloration of textile materials containing organic derivative of cellulose with leuco sulfuric esters of vat dyestuffs



Patented Oct. 14, 1947 UNITED STATES PATENT OFFICE Cyril M. Croft and Walter H. Hindle, Cumberland, Md., assignors to Ccianese Corporation of America, a corporation of Delaware No Drawing. Application September 19, 1942, Serial No. 458,960

7 Claims.

This invention relates to the dyeing of organic derivative of cellulose textile materials and relates more particularly to the union dyeing of mixed textile materials containing both filaments and fibers having a basis of an organic derivative of cellulose as well as filaments and fibers having a basis of cellulose.

An object of our invention is to dye organic derivative of cellulose textile materials rapidly and economically in colors extremely fast to light, washing and acid fading.

Another object of our invention is the union dyeing of mixed fabrics comprising organic derivative of cellulose textile materials mixed with textile materials such as cotton and regenerated cellulose to obtain a mixed fabric dyed in a uniform solid shade.

Still another object of our invention is to produce union dyeings employing a single dye bath for coloring the component fibers of the mixed fabric to obtain a uniform solid shade.

Other objects of our invention will appear from the following detailed description.

In the coloration of textile materials by means of dye baths it is highly desirable, especially from the point of view of economy, that the depth of shade desired in the textile material be reached with as short an immersion time as possible. When dyeing organic derivative of cellulose textile materials, however, it has been found that these materials are dyed more slowly than other textile materials since they are less absorbent and the dye liquor in the dye bath does not penetrate them as rapidly or as completely as other textile materials. Many dyestuffs when applied to organic derivative of cellulose materials from aqueous baths yield dyeings which are far from satisfactory. Consequently, long periods of immersion and manipulation are usually required in order to dye the textile materials in sufliciently deep shades which are fast to washing and to light and acid fading. When producing union dyeings on mixed fabrics containing organic derivative of cellulose and other textile material such as cotton or regenerated cellulose, the usual practice is to dye each material separately. This may be accomplished by employing separate dye baths, each containing dyestuffs having an afllnity for one of the textile materials, or by employing a single dye bath containing a plurality of dyestuffs, one or more of which has an aflinity for organic derivative of cellulose materials while the others have an affinity for the cotton or regenerated cellulose yarns or fibers. In order to produce satisfactory union dyeings in solid uniform shades, much skillful .dye bath formulation and manipulation are necessary; While acceptable union and other dyeings may be produced by such involved processes. not only are they time-consuming but it is observed that with many dyestuffs the dyed fabrics frequently exhibit poor resistance to light and acid fading as well as to washing.

We have now discovered that organic derivative of cellulose textile materials, as well as mixed materials comprising organic derivative of cellulose yarns or fibers and cellulosic materials such as cotton and regenerated cellulose yarns and fibers, may be dyed rapidly in deep; uniform shades which are extremely fast to washing, to light and to acid fading. These desirable results may be achieved if said textile materials are dyed with dyestuffs comprising the sulfuric acid esters of leuco vat dyestuffs in a dye bath comprising an aqueous organic liquid medium which has at least a swelling or softening action on the organic derivative of cellulose inateriali While ordinary methods of dyeing may} be emrpioyed utilizing our novel dyeing process, we preferably employ mechanical impregnation methods.

The aqueous organic liquid medium employed for applying the leuco vat dye esters may comprise an aqueous solution of a lower aliphatic alcohol or ketone which exerts at least'a swelling or softening action on the organic derivative of cellulose materials. While we preferably em ploy an aqueous solution of ethyl alcohpl as the liquid dyeing medium, other alcohols {such as methyl alcohol, propyl alcohol, isopropyl alcohol; n-butyl alcohol, secondary butyl alcohol, tertiary butyl alcohol, n-amyl alcohol, secondary amyl alcohol, tertiary amyl alcohol, and also ketones such as acetone and methyl ethyl ketone may be employed. When ethyl alcohol is'empioyed in the aqueous dye liquor it may comprise from about 50 to 80% by weight. Preferably, it comprises about by weight of the dye bath.

The dye liquor may be applied in various ways, but to obtain optimum results we employ mechanical impregnation methods suchas padding. Thus, as a continuous process, a fabric maybe unwound from aroli, passed through the dye liquor containing a leuco vat dye sulfuric acid ester, then between the nipping rolls of a padding mangle which are set to permit a predetermined quantity of liquor to remain in the fabric, and dried rapidly. When dry, the fabric is entered into a bath maintained at a suitable temperature in which the leuco vat dye on the fabric may be oxidized. By oxidation from the leuco form, the desired color. is produced on the fabric. Other textile material such as yarn in the form of hanks, staple fiber in the form of a top, and the like, may likewise be dyed by our novel process employing a very short processing cycle.

The drying of the fabric or other terial after impregnation may be carried out conveniently by passing said materials through a chamber through which heated air is'clrculated. The air may be heated to a temperature of from 180 to 205 F. for rapid drying and to, say 160 to 180 F. for less rapid drying.

The organic derivative of cellulose fabrics, tops, yarns or other textile materials which may be dyed in accordance with my process may be cellulose esters or cellulose ethers. Examples of cellulose esters are cellulose acetate, cellulose propionate, cellulose butyrate, and mixed esters such as cellulose acetate-propionate and cellulose acetate-butyrate. while examples of, cellulose other are ethyl cellulose and benzyl cellulose. Other'textile materials which may be dyed by our process are those which are cellulosic in nature such as cotton or regenerated cellulose.

As stated, yarns of organic derivative of cellulose materials such as, for example, cellulose acetate may be woven together with yarns of regenerated cellulose or cotton to form mixed fabrics.

These mixed fabrics may be dyed in solid shades by our novel process employing the same dye- 3 parts by weight of "Algosol Green IBW," a leuco vat dye sulfuric acid ester, are dissolved in 250 parts by weight of water at 86 F. To this solution are added 3 parts of sodium nitrite and 590 parts by welghtof ethyl alcohol. The solution obtained is employed as the dye bath.

A cellulose acetate fabric of a satin weave is passed through the dye solution at such speed that it is immersed therein for 2 seconds. The excess liquor is removed by passing thefabric through the rolls of a padding mangle. The rolls are so spaced that about 40% on the weight of the fabric of dye-liquor is retained thereon. 1 The wet fabric is then passed to a drying chamber where it is dried rapidly by means of air heated to 200 F. After drying, the fabric is immersed V for minutes in a 0.75% aqueous solution of sulfuric acid to develop the color. The solution is maintained at 95 F. After the color is developed by immersion in the above solution the fabric is washed, lightly scoured and dried. By this process the fabric is dyed a bright green which is fast to light and washing and does not fade on 40 hour exposure to an acid atmosphere. No color change occurs in the dyed fabric even after a 75 hour exposure in a standard light fastness tester, which indicates an unusual degree of light fastness.

Example II A mixed fabric of cellulose acetate and regenerated cellulose containing 50% of cellulose textile maacetate and 50% of regenerated cellulose is dyed in a solid violet shade as follows:

3 parts by weight of Algosoljrilliant Violet 14R," a leuco vat dye sulfuric "acid ester, are dissolved in 250 parts by weight of water atilfi" F. After solution, there are added 3 parts by weight of sodium nitrite and 590 parts by weight of ethyl alcohol. The mixed fabric is passed through this dye liquor at such speed that it is immersed therein for 2 seconds. The excess liquor is removed by passing the fabric through a padding mangle the rolls of which are set so that 50% of liquor on the 'weight of the fabric remains thereon. The fabric ous solution of sulfuric acid maintained at 959 F.

. The fabric is permitted to remain therein for 15 minutes to oxidize the leuco vat dye and it is then washed, lightly scoured and dried. The fabric isdyed a solid violet shade, both the cellulose acetate and the regenerated cellulose being dyed to the same uniform shade. The dyed fabric is very fast to washing and to acid fading, no change being observed in the latter test even after a 40 hour exposure. The dyed fabric is likewise very fast to light and exhibits no change in shade even after hours of exposure in a standard light fastness tester.

It is to be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of our invention. Having described our invention, what we desire to secure by Letters Patent is:

1. Method for the coloration of cellulose acetate textile material, which comprises impregnating said material with an aqueous ethyl alcohol solution of a leuco vat dyestuff sulfuric acid ester consisting of about 70% by weight of said alcohol and about 30% by weight of water,

drying said impregnated material, and causing said leuco vat dyestuif sulfuric acid ester to be oxidized.

2. Method for the coloration in a, uniform solid shade of a mixed textile material containing cellulose acetate and regenerated cellulose yarns and fibers, which comprises impregnating said mixed material with an aqueous ethyl alcohol solution of a leuco vat dyestuif sulfuric acid ester consisting of about 70% by weight of said alcohol and about 30% by weight'of water, drying said impregnated material, and causing said leuco vat dyestuif sulfuric acid ester to be oxidized.

3. Method for the coloration of cellulose acetate textile material, which comprises impregnating said material with an aqueous ethyl alcohol solution of a leuco vat dyestuff sulfuric acid ester consisting of about 70% by weight of said alcohol and about 30% by weight of water, drying said impregnated material by means of air heated to about 200 F., and causing said leuco vat dyestufi sulfuric acid ester to be oxidized.

4. Method for the coloration in a uniform solid shade of a mixed textile material containing cellulose acetate. and regenerated cellulose yarns and fibers, which comprises impregnating said mixed material with an aqueous ethyl alcohol solution of a leuco vat dyestuif sulfuric acid ester consisting of about 70% by-weight of said alcohol and about 30% by weight of water, drying said impregnated material by means of air heated to about 200 F., and causing said leuco vat dyestufi sulfuric acid ester to be oxidized.

5. Method for the coloration in a uniform solid shade of a mixed textile material containing an organic derivative of cellulose and regenerated cellulose yarns and fibers, which comprises impregnating said mixed material with an aqueous ethyl alcohol solution of a leuco vat dyestuif sulfuric acid ester consisting of from 50 to 80% by weight of said alcohol and from 50 to 20% by weight of water, drying said impregnated material, and causing said leuco vat dyestufl. sulfuric acid ester to be oxidized.

6. Method for the coloration in a uniform solid shade of a mixed textile material containing cellulose acetate and regenerated cellulose yarns and fibers, which comprises impregnating said mixed material with an aqueous ethyl alcohol solution of a leuco vat dyestuil' sulfuric acid ester consisting of from 50 to 80% by weight of said alcohol and from 50 to 20% by weight of water, drying said impregnated material, and causing said leuco vat dyestuif sulfuric acid ester to be oxidized.

7. The method of imparting a uniform coloration to a mixed textile material consisting of cellulose acetate and cellulose fibers by impregnating the mixed material with a solution of ethyl alcohol and a sulfuric acid ester of a leuco vat 6 dyestufif in water and developing the dyestufl' by The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,292,433 Croft Aug; 11, 1942 2,182,964 Dreyfus et al Dec. 12, 1939 2,218,628 Sowter Oct. 22, 1940 2,196,270 Moncriefl et a1. Apr. 9, 1940 2,274,751 Sowter et al Mar. 3, 1942 1,968,856 Rivat Aug. 7, 1934 2,344,973 Croft et al. Mar. 28, 1944 FOREIGN PATENTS Number Country Date 274,094 Great Britain Oct. 4, 1928 843,546 France Mar. 27, 1939 500,960 Great Britain Feb. 17, 1939 

